大型卷筒熔化极药芯焊丝气体保护焊堆焊工艺

介绍铜管拉拔机关键部件拉拔卷筒孚用熔化极药芯焊丝气体保护焊堆焊耐磨层的堆焊工艺。堆焊材料选用抗裂性好的ＰＫ－ＹＤ２１２焊丝，单层硬度〉ＨＲＣ５０。所确定的堆焊工艺可行，工件不预热，熔合区窄，堆焊合金释稀率低。     

熔化极气体保护焊用焊丝与保护气体的匹配关系

综述了GMAW两类焊丝与3种保护气体匹配关系。结果表明,焊丝对保护气体的匹配工艺特征各异,其中,两种焊丝对Ar+CO2的匹配工艺都显示最佳。在焊丝与保护气匹配关系下,实现喷射过渡的条件是:阳极斑点面积足够大,电磁力方向向下,焊接电流超过临界电流,三者缺一不可。对于实心焊丝,Ar+CO2富氩混合气体工艺的适应性更好。对于药芯焊丝,Ar+CO2富氩混合气体工艺的适应性与100%CO2保护气相当。工程应用表明,纯CO2和Ar+CO2富氩混合气体对两种焊丝都能获得符合要求的焊接接头,后者的工艺性可能更好一些,但气孔(压坑)敏感性更大些。     

CO2气体保护焊实心焊丝电弧物理特征分析

采用汉诺威弧焊质量分析仪和焊接过程高速摄影,测试分析了在CO2气体保护焊条件下,实心焊丝电弧物理特性,发现熔滴短路时间大于1 ms,正常短路频率越高,平均短路时间越短,飞溅越小,焊接过程越稳定.提出用24 V/180 A参数下大于1 ms平均短路时间、熔滴平均短路频率和短路时间大于4 ms短路频率作为判据来定量评价实心焊丝工艺性.     

等离子-熔化极气体保护焊电弧特性研究现状

等离子-熔化极气体保护焊的电弧形态和熔滴过渡方式直接关系到焊缝质量,采用不同的电极连接形式,如直流正接、直流反接,电弧形态及熔滴过渡方式均不同;主要介绍了目前等离子-熔化极气体保护焊在采用不同的电极连接形式下,不同的电弧形态和熔滴过渡方式,以及电弧成分组成和温度分布;通过对熔化极等离子弧静特性等方面的研究发现,熔化极电流的大小不是由焊丝与工件间的电压决定的,而是由导电嘴与焊丝端部处的等离子弧电位差决定的,并决定电流的方向.     

药芯焊丝熔化极CO2气体保护焊焊接不锈钢复合板的工艺研究

常规复合板焊接中的过渡层、面层均采用焊条电弧焊(SMAW)焊接,生产效率低、工人劳动强度大,焊接质量受焊工的技术水平影响很大.不锈钢药芯焊丝CO2气保护焊(FCAW)具有生产效率高、电弧燃烧稳定、焊接飞溅小、工艺性能良好、质量高、易操作、综合成本低等优点,通过焊接工艺评定试验,确定了不锈钢药芯焊丝CO2气保护焊的焊接性,并经理化试验验证了焊缝的力学性能.     

自保护药芯焊丝电弧稳定性分析

采用汉诺成焊接质量分析仪对自保护药芯焊丝(SSFCW)的焊接电参数进行了测试分析,发现电压标准偏差△ U越小,电流标准偏差△I也越小,其变异系数δ U和δI也越小,电弧稳定性越好.通过对U-I图和电弧电压偏差直方图的分析,提取出某些反映电弧稳定性的信息,该信息对于评定自保护药芯焊丝工艺性能提供了参考.U-I图中电弧瞬时工作点轨迹越集中,电孤电压偏差直方图分布越集中越高,电弧稳定性越好.     

熔化极气体保护焊电流与电压调节

在应用熔化极气体保护焊的基础上,分析焊接电流和电弧电压对焊缝成形的影响,探究焊接电流与电弧电压匹配对焊接电弧特性的影响规律,总结正确调节焊接电流与电弧电压的基本方法和操作技能,正确调节焊接电流与电弧电压是熔化极气体保护焊技术推广与应用的关键因素。     

LiF对自保护药芯焊丝电弧稳定性的影响

采用AHXV电弧分析仪研究了芯料组成中LiF对自保护药芯焊丝焊接电弧稳定性的影响。研究结果表明，在自保护药芯焊丝中加入LiF，能够减小焊接电流的波动范围，使焊接电弧的稳定性得到改善，但LiF的加入量应控制在合适的范围内，加入量太少稳弧作用不明显，加入量过多能导致焊接飞溅增大及由于吸潮而带来的的气孔等问题。     

Estimation of wire extension length using neural network in MIG welding

Measuring arc length is important to obtain good welding quality in spite of variation of torch height. Therefore, it is necessary to detect arc behaviour in the transient state in addition to the steady state. For this purpose, this paper proposes neural network models which output the present wire extension from the data relating to wire melting, such as welding current, current pickup voltage and wire feed rate in every sampling period. Since performance of the neural network model depends on threshold functions, authors investigate the performance of the neural network models based on both sigmoid function (SF) and radial base function (RBF).

To confirm the validity of these systems, fundamental experiments were carried out. The arc was directly observed and recorded as image data using a high-speed camera. The output data from the neural network were compared with the measured data, which were obtained from every captured image. It was found that the neural network model based on the RBF is useful than the SF to estimate the wire extension length in MIG welding because of better responses in the transient state and smaller steady state error.     

焊接电流对双丝间接电弧焊电弧特性的影响

主要研究了焊丝伸出长度对焊接电流、电弧电压以及焊接电流对双丝问接电弧气体保护焊电弧特性的影响。结果表明,随着焊丝伸出长度的增加,焊接电流减小;双丝间接电弧气体保护焊负极焊丝的熔化速度随着焊接电流的增加而明显增大,正极焊丝的熔化速度随焊接电流的增加而缓慢增大,两者均随着电弧电压的增加而减小;随着焊接电流的增大熔滴变细;双丝问接电弧气体保护焊有多种电弧形态。     

A numerical model of wire melting rate in variable-polarity submerged arc welding

Based on the pre-existing wire melting rate model of direct-current submerged arc welding （ DC-SAW） , a new numerical model of wire melting rate was developed for variable-polarity submerged are welding （VP-SAW） by accounting for the combined effects of duty cycle β and offset α. The experimental measurements are in a good agreement with the results calculated by this new wire melting rate model, with the maximum discrepancy being less than 10%. Therefore it is evident that this new numerical model can successfully describe the dependence of wire melting rate on the duty cycle β and offset α.     

Research on droplet transfer in oscillating arc narrow gap GMA welding

In this paper, the droplet transfer in oscillating arc narrow gap gas metal arc （ GMA ） welding was studied. According to the experimental results, the oscillating arc has effect on the droplet transfer mode. The droplet transfer frequency in narrow gap groove is higher than that in bead-on-plate welding. Because of the change of arc location in narrow gap groove, the droplet transfer in oscillating arc narrow gap changes regularly. The droplet transfer frequency near groove sidewall is higher than that at the middle of narrow gap groove.     

The alternate wire-feed control in the automatic CO2 arc welding

In the automatic CO2 arc welding, the alteration of the vertical distance between the welding torch and the workpiece has a strong effect on the welding parameters such as welding current and voltage, with the result that the appearance and quality of weld are not steady. To weaken the influence of the distance alteration, a method is put forward in the paper. The method is that the alternate wire-feed control is used for compensating the welding current. On the basis of theoretical analysis, a static numerical model for alternate wire-feed control is established. The experiments show that the model-based regulation of the wire feed rate can compensate the welding current and ensure the appearance of weld. When the alteration of vertical distance between the torch and the workpiece is greater, not only is the wire feed rate regulated, but the output voltage of the power source is adjusted to ensure the appearance and quality of weld.     

自保护药芯焊丝全位置焊接电弧稳定性分析与评价

采用高速摄像仪和汉诺威弧焊质量分析仪对三种市售X70管线用自保护药芯焊丝全位置焊接的熔滴过渡及电弧稳定性进行观察分析.结果表明,全位置焊接电弧稳定性为1号焊丝最好,3号居中,2号最差;电流变异系数比标准差更能准确地反映电弧稳定性;单凭平均短路时间不能作为判定电弧稳定性的依据,必须结合短路时间频次分布图才有意义;短路过渡时电弧电压概率密度分布为双驼峰形状,双驼峰处曲线的概率密度分布及整条曲线的收敛情况可作为评定电弧稳定性的重要参考依据.     

双丝埋弧焊接头性能研究

在16Mn钢板上进行双丝自动埋弧焊工艺试验,得到了不同焊接速度下的焊件.对不同工艺参数下得到的焊接接头试样进行了拉伸试验、硬度测试以及金属显微组织观察,并计算了双丝自动埋弧焊时的熔敷率.结果表明:采用双丝埋弧焊得到的焊缝外形美观;金属熔敷率与焊接速度成反比;随着焊接速度的降低焊接线能量相应的增大,较长的高温停留时间会促...     

镁合金活性焊丝TIG焊

选择单一成分的常见化合物作为活性剂,涂敷于焊丝表面形成活性焊丝,并进行TIG填丝焊接试验.结果表明,在镁合金活性焊丝TIG焊接过程中,活性剂仍能起到增加焊接熔深的作用.氯化物活性剂对熔深的增加效果最为明显,熔深较普通焊丝增加最大可达3倍以上.研究发现对镁合金TIG焊熔深增加效果好的活性剂的沸点集中于900℃附近区间.用活性焊丝焊接时熔滴与熔池金属的融合能力变差,填丝性能较普通焊丝相比有所降低.     

铝合金MIG焊丝伸出长度视觉提取算法及动态过程辨识

建立了一种基于视觉传感的铝合金MIG焊丝伸出长度检测系统,并提出了相应的图像处理算法,通过使用CCD摄像机,实时获取焊接区图像,根据焊丝特征定位其在图像中的纵坐标,然后对图像进行剪切,移位并叠加,使焊丝特征与背景之间的差别得到强化并提取焊丝伸出长度信息,结果表明,该算法快速有效.在以上工作的基础上,设计了阶跃响应试验,对焊丝伸出长度受送丝速度的影响规律进行了辩识,得到了数学模型,为铝合金MIG焊接过程中焊丝伸出长度传感与控制奠定了基础.